<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>体验CSS</title>
</head>
<link rel="stylesheet" href="my.css">

<body>
    <P>这是P标签</P>
    <div>这是div标签</div>
</body>

</html>